The present invention relates to a method for producing an incandescent light source and a light source obtained according to such method.
The first working step followed for purposes of producing filaments for incandescent light sources typically consists of preparing a mixture of tungsten and metallic additives, which is subsequently sintered in the form of bars.
The bars thus obtained are then subjected to hammering and drawing with successive passages, until obtaining a continuous wire with the desired diameter; said wire is subsequently wound in a spiral and cut to the required length to be ready, after a stabilising heat treatment, to be mounted onto a respective support to be inserted in the light source.
In the case of common incandescent lamps, the filament is maintained in position thanks to respective end conductors and intermediate hooks; the conductors serve both as supports and to carry electrical power to the filament, and for this reason they are connected to the base of the lamp; the hooks instead serve solely as supports. The electrical connections between the filament and the conductors are mainly obtained by soldering, for instance by means of capacitive discharge, or by folding and upsetting the conductor on the filament. Since the hooks do not have to provide electrical contact, they are generally folded in loops, through which the filament passes.
Other types of light sources provide for the use of matrices of filaments able to emit light by incandescence when powered by an electrical current, as well as the use of electronic control means for the lighting of some or all filaments in the matrix.
The individual filaments can be obtained with multiple coupled filaments (two, three, or more), or with a single filament wound in a simple or multiple spiral or, in the simplest case, they can consist of a segment of individual filament. The aforesaid matrix consists of a quantity of filaments connected in various ways, for instance in series, in parallel, in series-parallel, in parallel-series, in a net configuration.
Regardless of the chosen configuration, the number of the filament in a matrix can be high, where the respective arrangement presupposes
connections between the power supply conductors and the filaments, and/or
connections between the filaments, and/or
connections of any conductors or hooks intermediate to the filaments.
One of the reasons limiting the wider use of light sources with filament matrices is currently constituted by the difficulty in obtaining the aforesaid connection in a simple, effective and economical manner.
Another difficulty to overcome is given by the fact that, especially when the number of filaments in a matrix is high, there are manufacturing problems linked to their positioning.